Eames has been watching the whole time. The truth is that most of his talent comes from observation and it's in people's both conscious and subconscious actions that he finds the most information. He watches as she begins to work her way through the dream (having watched the dream, as well) and looks out for projections and what they might do. He's very self-serving and counts on his survival instincts to get him through any situation. It also just helps to have camouflage.

He watches as she sights him and lets out a languid, lazy smile as Eames reclines in the chair. "Gentlemen do prefer blondes," he replies in a dry American accent, shifting again, but this time it's into a direct mimic of her copy of Sophia Loren, right down to the dress. "Impressed yet?"